Method of perforation of well pipe



July 16, 1963 G. c. TERREL. 3,097,693

METHOD oF PERFORATION oF WELL PIPE Filed July 214, 1960 f ,",uoron secrlon g/Penmmuow 1 INVENTOR. GARLAND c. TERREL,

ATTORNEY.

United States Patent 3,097,693 METHOD OF PERFORATION OF WELL PIPE Garland C. Terrel, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed July 21, 1960, Ser. No. 44,339 1 Claim. (Cl. 166-35) This invention relates to a method of perforating in wells to establish communication between twoI parallel, non-concentric, spaced-apart pipe strings.

lIn certain Iwell operation-s, as for example when it is desired to establish subsurface communication between pipe strings during bloWou-ts, workovers, etc., i-t is lnecessary to direct the iire ot a gun perforator positioned in one pipe string to perforate one or more other pipe strings located in a well completed with multiple pipe strings. Various methods are employed ffor establishing comanuncation between pipe strings arranged in a borehole, and these include the use ot bullet, jet, chemical, and abrasive-type pertorators as Well as vari-ous types of perforator orienting devices, such as radio-activity and magnetic devices, gun guides, etc.

In some wells, the distance between any two of a plurality of spaced-apart pipe strings may vary, such that the amount of penetration of the perforator necessary to establish communication between the pipe strings, without penetrating completely through the other side of the pipe string with which communication is being established, can-not be accurately determined. Thus, a perforator that has suicient penetration energy to penetrate another pipe string with which it is desired to establish communication where the pipe strings |are lseparated 'by the maximum possible distance may result in perforating completely through this pipe :string if the pipe strings are located or positioned a minimum distance apart. Perf-oration completely through the other pipe string is not desired because the additional opening may fluidly cornmunicate with la surrounding formation, or a third pipe string, etc.

The present invention provides a solution to this problem by :arranging an energy absorber tool in the second pipe string to absorb the energy yof the perforator and prevent perforation or damage of the opposite Wall of this pipe string. The tool is retrieuable, and once the perforation has been made, may be retrieved, if desired, to prevent obstructing the bore of the second pipe string.

Therefore, a primary object of the present invention is to provide an improved method of perforating in wells to establish subsurface communication between two nonconcentric, spaced-apart pipe strings.

This an-d other objects of the invention will be apparent from a more detailed description of the invention taken in conjunction with the drawings wherein:

PIG. l is a cross-sectional view of the earths subsurface showing two parallel, `spaced-apart pipe strings arranged in a borehole; in one is arranged `a pipe perf-crater and in the other pipe string is positioned an energy absorber tool; also illustrated in this ligure is one type of pipe perforator `orienting instrumentation;

FIG. 2 is a view taken on lines 2-2 of iFlG. 1 and illustrates the positions of the pipe :strings when they are spaced some .distance apar-t; and

FIG. 3 is a view similar to that shown in FlG. 2 illustrating these pipe strings positioned close together.

yReferring to the drawings in greater detail, in FIG. 1 is shown a borehole which has arranged in it two parallel, non-concentric spaced-apart pipe strings 1-1 and 12. A pipe perforator 13;` is suspended on a wire line 14 in pipe string `1.1. Perforator i13 may be of any desired type; i.e., jet, bullet, chemical, or abrasive. An

ice

energy absorbing tool 15 is suspended in pipe string 12 on la wire line l16. The absorber may be an iron, steel or lead bar, or in the case of the use of chemical or abrasive perforators, the absorber may be formed of rubber or ceramic material. Although the tool as shown appears cylindrically shaped, any desired conliguration may be employed instead.

For the purpose of illustration, a particular type radioactivity orienting device is provided. In this case, the radioactivity technique utilizes a tocu-sed radiation detector 17 connected to pipe perforator i1-3 and a radiation source 1-8 connected to energy absorber tool 15. This technique and apparatus for performing it are shown and described in U.S. patent application Serial No. 780,517 entitled Method and Apparatus for Well Oper-ations, dated December l5, 1958, by James T. Brurnble, Jr.

As mentioned previously, other techniques may be employed. For example, both the source of radiation and a focused detector may be positioned on the perforator, This latter technique is shown and described in U.S. patent Serial No. 780,5(24 entitled Method and Apparatus for Operating in Wells, iiled December 15, 1958, by Harry S. Arendt.

Another technique may be used which places the radioactive source on the perforator and the focused detector on the energy absorber tool. Any of these techniques are applicable. Various means may be used to rotate the gun perorator to ascertain the direction of the other pipe string. In FIG. 1 a motor 19 is shown which by means of the shaft connection 20 rotates perforator 13 and detector l17 in a 3601 arc in order to establish location of pipe string 12, and thus the direction of tire of pipeperforator 113. U.S. patent application Serial No. 780,387 entitled Well Operation Method and Apparatus filed December 15, 1958, by John C. M'cDuiiie, Ir. discloses equipment tor carrying out lthis. opera-tion. The patent applications mentioned previously disclose other mechanical type means for rotating the pipe perforator and detector through a 360 arc, and these means may be utilized instead of the motor-driven rotator.

In operation, pipe perforator 13, detector I1-7 .and motor 19 are lowered on wire line 14 to the subsurface location |at which it is ldesired to establish communication between pipe strings 11 and `12. The energy absorber 15 and radioactive source 18 are lowered on wire line 16 in pipe string 12 to the same depth location so that radioactive source 18 is at approximately the same level as detector 71. Motor 19 is the actuator which rotates pipe perforator 13 and focused detector 17. lIn its circumferential traverse the direction of radioactive material 18 and thus the direction of pipe string 12 are established. The perforator elements of perforator 13 are then faced in the direction of pipe string 12 Iand activated to penetrate both pipe string 1'1 and pipe string 12.

As shown in FIG. 2, the per-forator penetrates the interior lof pipe string -12 and establishes communication between .the pipe strings. Prob ably, it would not be necessary .to utilize the energy absorber tool 415 when the pipe strings 11 :and `1-2 are spaced suiciently tar apart as shown in FIG. 2. However, the distance between pipe strings 11 Iand 12 is not lknown, and they may be positioned adjacent to each other as illustrated in FlG. 3. In that event, the perforator would penetrate through the wall of pipe string 12 acl-jacent to pipe string 11 and continue on and penetrate the opposite `wall of pipe string 12. By using the energy absorber 115, penetration of the opposite wall of pipe string 12 is prevented.

Having :tully described the method, apparatus, and objects of my invention, I claim:

A method 4for perforating in wells to establish cornmunication between two parallel nonconcentric pipe strings comprising the steps of lowering a pipe perforator in one pipe string having a selected radial direction of perfonation to adjacent the depth in a well to which it is desired -to establish communication between the two pipe strings; lowering in the other pipe string perforator enengy `absorbing means to the salme depth to which the perforator was lowered; detecting the radial direction of said other pipe string relative to the direction of perforation of said perforator; orienting said perforator so that the direction of perforation faces in the direction of the other pipe string; and then `actuating the perforator to perforate both pipe strings to establish communication between the pipe strings, the energy absorbing means absorbing energy of the perforator in excess of that necessary to perforate Iand establish communication between the pipe strings.

References Cited in the le of this patent UNITED STATES PATENTS V2,228,623 Ennis Ian. 14, 1941 2,436,503 Cleveland Feb. 24, 1948 2,476,137 Doll July 12, 1949 2,785,754 True Mar. 19, 1957 2,891,620 Bielstein June 23, 1959 

